The invention relates to a steam iron comprising a water reservoir, a steam chamber and a water-supply system for conveying water from the reservoir to the steam chamber, said iron comprising means for reducing the deposition of scale in the water-supply system.
Such a steam iron is known per se from United States Patent Specification U.S. Pat. No. 5,063,697. Said Specification more particularly describes a steam iron comprising a detachable cartridge which contains an ion exchanger. When the iron is in operation, the water reservoir is filled with tap water which, dependent on the quality of the local tap water, is hard or not so hard. This water is conveyed from the reservoir via the cartridge to the steam chamber. By means of the ion exchanger, the tap water is (partially) softened, so that the deposition of scale (predominantly calcium carbonate) during operation of the iron is substantially reduced at the location of the water-supply system and the steam chamber. In particular the deposition of scale in the water-supply system constitutes a major problem because it may cause the conduit of the water to be vaporized to become obstructed. Obstruction of the conduit renders the steam iron unserviceable.
The drawback of the known steam iron is that the detachable cartridge containing the ion exchanger must be replaced by a "fresh" cartridge after it has been used for a number of hours. This is caused by the fact that the capacity of the customary ion exchangers to soften tap water is relatively small. Partly due to the limited volume of the water reservoir it is impossible, in practice, to provide the steam iron with a quantity of ion exchanger which is sufficient to soften the overall quantity of water used during the entire life of the device. Owing to this limitation, exchangeable cartridges containing ion exchanger are used at present. However, this solution to the problem of scale deposition in the iron is inconvenient. In addition, this solution causes constructional problems due to the exchangeability of the cartridge, which may be subject to leakage.